Fast math trick for adding a series of numbers
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- เผยแพร่เมื่อ 19 ก.ย. 2024
- How fast can you add 1+2+3+4+5+6+7+8+9+10? In four seconds? What about all the numbers 1 to 100? This video shows a fast and easy math trick that will have you adding series of numbers so fast you will not believe it! This uses the ideas of averages, as you will see in the math trick lesson. To donate to the tecmath channel: paypal.me/tecm... To donate to the tecmath channel: paypal.me/tecm...
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I really love your voice. It is a big part of the reason I went back to watch more of these.
Hey how does it feel to get a reply after 7 years???
@@alishaswain9216 maybe he lost his account
General formula: (x + y) * ((y - x) / z + 1) / 2
(where x is the start number, y is the end number and z is the step number)
Example: x = 1
y = 7
z = 2
(x + y) * ((y - x) / z + 1) / 2 = 16 because 1+3+5+7 = 16
Er, no that's incorrect. Lol, the example you give isn't correct either, as based on your 'general formula' the answer should be 8 and not 16!
Check your workings out (simple subscription ie yr 4) :D
+Jason Murtagh Check your mathematics once again. ;)
Well, those were definitely some clever shortcuts. Thanks!
Don't care. It was this video that I saw it from.
🤯 I’ve been trying to figure this out for way too long I knew it was simple but i just couldn’t figure this out on my own. Thanks!
Very useful trick. Thanks.
thankyou im in year 7 and i suck at maths and you help!🍉
what about noncontinuous no.s 20+23+25+26+27+30 its giving 150 while actual ans is 151. i guess there might be some difference b/w digits issue.
Omg you saved my life
what do you do for series that aren't continuous? how to calculate those?
You will get an approximate answer vs adding up all the numbers to get an accurate answer.
Very nice trick
I am your 89,600th suscriber
How do you do the opposite tho?
this is only for continuous series right?
yep
Those mentioning n(n+1)/2 I think you'll find this will only work if you're sequence starts from 1. If you're adding a sequence of say 15-30 that formula/rule is incorrect..;)
Nope. You can modify it to be n(n+m)/2 when m represents the last number in the sequence. You are welcome ;)
You'll have to show me, as that ain't working for me! Maybe I'm just thick- which to be fair I probably am? Lol
75-90? n(n+m)/2....
Hmm... perhaps it should be (n+m)(m-n)/2. My fault.
lmao, no that don't work either!
I'll put everyone out of their misery, it's actually n(f+l)/2
n being number of numbers (not digits!)
f being first number
l being last number
This WORKS for any regular sequence as all you're doing is finding the average value!
if i had u for my teacher at school i;d have been ALLRITE !!
Now I need to figure out how to do this in code
How to answer if the numbers is not continuesly?
Thank sirji your trick is amazing.
@@UndergroundBird welcome for giving me quickly reply 🙏🏻
Thankkkk youuu sooo muchhh😭👍❤️
all thanks goes to Gauss
There is an more easier way to this...use N(N+1)/2 forumla..where n=number of digits!
This only works if your series starts from 1.
Thank you buddy!!
It would've been easier if you added 1+9 gives u 10 2+8 gives you 10 7+3 gives you 10 and 6+4 gives you 10 . 10 times 4 is 40 plus the 15 left over gives 55
I don’t think so
If you had to add 1 to 200 for example it would take too lomg
I know how to add up a group of all continous odd numbers AND a group of all continous even numbers AND continous numbers like:
(For example)
3+6+9+12......369 = 22878
4+8+12+16.......892 = 99904.
And so on.
Elson Ngai how?
Is there a trick for an odd number of numbers?
Its the same trick. Take any group of numbers add the start (lowest) number to the end (highest) number and then divide by 2 to get an average. Now multiply your average by the total number of numbers in your group. Try it and see. e.g. {21 23 25 27 29 31 33 35 37}
how do you calculate triangular numbers? please help...
please.... so 1,3,6,10,15,21... so on
***** no i found the rule out
If you wanna find the x triangular number
X^2 +x
------------
2
***** i was ASKING FOR THE FORMULA
***** i knew that ages ago
triangular numbers are the partial sum of the sequence ( 1, 2, 3, 4, 5, .........., n )
I guess this trick will only work if the frequency are the same between each numbers
its called complements method in math.
Nope. This is Gauss' method and it was supposedly invented by him when he was 10. His teacher was so impressed that he sponsored Gauss' education.
@@present403 lol
By adding which 6 numbers answer is 15
*KEMPNER HIGH SCHOOL PEOPLE THIS WILL WORK!!!*
5+6+7+8+9+10+11+12+13+14=95
THE FASTEST WAY IS TO TAKE THE LAST NUMBER
SUBTRACT 5 THEN ADD A DIGIT OF 5 AT THE END
This is not working
Careful when there’s an odd number of numbers
I haven't watch finish this video but I read the description and I know that 1+2+3+4+5+6+7+8+9+10.....+100 is equal to 5050
obviously you are asian
Farishta Ahmadzoay you are correct
Gauss method FTw
55
not a trck it using the formula n(n+1)/2
A formula is a technique
Noice
1+2+3+4+5+6+7+8+9 what is the answer.
1+9=10.10/2=5 so 5*10=50..this is wrong...
actual answer is 45 k
nag raj you mean 5*9, multiply last number in series
5 times 9 not 10= 45
I did not undestand anything
thats so easy
Gauss